Merge pull request #21 from FriendlyCaptcha/agreenberg/add-missing-fi…

…le-extensions

Add missing '.md' file extensions to links

docs/guides/upgrading-from-v1/index.md

@@ -8,11 +8,11 @@ To learn more about the ways v2 improves upon v1, and why upgrading is worth the
 
 ### Script tag installation
 
-If you installed Friendly Captcha to your website by adding a `<script>` tag, follow [this guide](./script).
+If you installed Friendly Captcha to your website by adding a `<script>` tag, follow [this guide](./script.md).
 
 ### Programmatic JavaScript API
 
-If you are using the Javascript API to programmatically create widgets, please follow [this guide](./javascript-api).
+If you are using the Javascript API to programmatically create widgets, please follow [this guide](./javascript-api.md).
 
 :::tip
 
@@ -24,4 +24,4 @@ We are working on bringing v2 support to all popular languages and frameworks.
 
 ## Back-end changes
 
-You will also need to make small changes to your back-end code. These are described in [this guide](./backend-integration).
+You will also need to make small changes to your back-end code. These are described in [this guide](./backend-integration.md).